A conventional refrigerator cools or freezes foodstuff by having an evaporator constituting a refrigeration cycle in a space formed by a refrigerator box, and disposing a heat insulating material in the box for insulating a cool air produced by the evaporator from an outside air.
Recently, a vacuum heat-insulator having a high heat-insulating characteristic is attracting a public attention from energy-saving and space-saving standpoints. Examples of such vacuum heat insulators are such as one which core material is made of hard-urethane-foam having continuous foam, covered by a gas-barring laminated film and then inside is vacuumed, and another one which inorganic material powder is filled in an inside bag, and the bag is put in an outside bag and then the outside bag is decompressed. Heat-insulating characteristic of those vacuum insulators is 2.5 times higher than that of foam resin insulator composed of hard or soft urethane-foam material.
The foam resin material used in the conventional refrigerator is not so effective as to prevent the heat-insulating material from burning from a fire, if a fire is broken out near the refrigerator and the heat-insulating box catches the fire. Using a vacuum heat-insulator having a high heat-insulating characteristic is an effective way for a refrigerator to enhance energy-saving characteristic and increase a storage capacity of the refrigerator. However, the vacuum heat-insulator using the foam resin as a core material does not much contribute to increasing non-flammability of the refrigerator. If a vacuum heat-insulator employs an inorganic-material powder, non-flammability of the insulator increases, however, because the material is hard to be molded into a heat-insulator, it is difficult to be used for a heat-insulator of a refrigerator. Moreover, as flammable hydrocarbon (HC) refrigerant is started to be used for preventing global warming, a refrigerator avoided from catching a fire is becoming more important. Yet the conventional heat-insulating material does not comply with such requirement.
The present invention is aimed to solve above conventional tasks and to provide a refrigerator which is safe for using a flammable refrigerant and high in energy saving property. The refrigerator uses a non-flammable vacuum heat-insulator made of a board-shape molded inorganic fiber in the refrigerator box, thus preventing the refrigerator box from catching an outside fire.